Field of the Invention
The present invention relates to a protein construct, useful for redirecting an existing immune response, toward an undesired target cell.
Background Information
Natural immune response is not sufficient to destroy undesired cells such as tumor cells. Many efforts have been made to target these cells, in order to obtain a better immune response or a direct cytotoxicity. In this purpose, bi-functional molecules, optionally heteromultimeric bi-functional molecules, have been proposed. In this context immunotoxins have been designed, that contain targeting domains that direct the molecules to target cells of interest (e.g., effector T lymphocytes) and toxic domains that kill the target cells. U.S. Pat. No. 6,492,498 describes a fusion protein molecule containing a toxic domain, a targeting domain, and at least one heterologous coupling moiety. U.S. Pat. No. 6,492,498 further describes multimeric forms of this protein molecule.
However such approach is still not fully satisfying. Firstly, all target cells are not destroyed. Secondly, immunotoxins that do not reach the target may be toxic to other cells.